cp-skill-write

## EXECUTE NOW **Target: $ARGUMENTS** All documents in the KB live in a **collection**: a directory under `kb/` with a local `COLLECTION.md`, such as `kb/notes/`, `kb/reference/`, `kb/instructions/`, or an installed library collection like `kb/commonplace/notes/`. Each collection that accepts writes has a `COLLECTION.md` with its purpose, intended contribution, quality goal, and linking conventions. Documents with frontmatter carry a path-valued `type:` that points to a type-spec doc, for example `type: kb/types/note.md` or `type: kb/reference/types/adr.md`. Files with no frontmatter are implicit `text`. ### Step 1 - Parse Arguments **Edit mode**: first argument is a path to an existing `.md` file. Read it, infer collection from the path, and read its `type:` path from frontmatter. If it has frontmatter but no `type:`, stop and fix that structural problem before editing. If it has no frontmatter, treat it as implicit `text`. Open the type-spec doc named by `type:` before making structural edits. **New-write mode**: everything else. Extract collection, type, and topic from the arguments. Default an unspecified collection to `notes` and an unspecified type to `kb/types/note.md`. If the requested type is an instruction and no collection is explicit, use collection `instructions`. For new writes, resolve the target collection to a directory under `kb/` with a local `COLLECTION.md`; shorthand names such as `notes` mean `kb/notes/`. Resolve the type independently of the coll...